It's really hard to know, isn't it? Would depend on who's already picked...but I'll play along.
If 4 QB's go, we have to assume that's Darnold, Rosen, Baker, and Allen. The other players that are VERY likely to be gone are Nelson, Barkley, and Chubb.
There will be 4 other players also gone by that point, likely 4 of this bunch - Smith, Edmunds, Minkah, Ward, Derwin James, Vita Vea
So to answer your question, the best options left at 12, will be whichever 2 of the players listed above haven't been selected. Depending on team needs, Ridley or one of the tackles (McGlinchey) could also be options.
That's how I see it anyway.